基本操作

包括檔案的建立、刪除、寫入、讀取

建立檔案和資料夾

// 建立檔案和資料夾
@Test
public void test1() throws Exception
{
    File file = new File("F:"+File.separator+"booway"+File.separator+"Java"+File.separator+"0711"+File.separator+"TestFile");
    File file2 = new File("TestFile");// 在專案的根目錄下建立
    // 判斷是否存在
    if (!file.exists
 
())
    {
        file.mkdirs();
        file.createNewFile();

        file2.mkdirs();
        file2.createNewFile();
    }
}

#

// 刪除檔案
@Test
public void test2() throws Exception
{
    String path = "F:"+File.separator+"booway"+File.separator+"Java"+File.separator+"0711"+File.separator+"test.txt"
 
;
    File file = new File(path);
    file.deleteOnExit();// 虛擬機器關閉後才刪除檔案

}

向檔案中寫內容

// 寫檔案
@Test
public void test4() throws Exception
{
    String path = "F:"+File.separator+"booway"+File.separator+"Java"+File.separator+"0711"+File.separator+"TestFile";
    File file = new File(path);

    // 覆蓋新增
    // FileOutputStream outputStream = new FileOutputStream(file);
 


    // 追加新增
    FileOutputStream outputStream = new FileOutputStream(file, true);
    for (int i = 0; i < 100; i++)
    {
        outputStream.write("hello world".getBytes());
    }

    // 清除快取
    outputStream.flush();
    // 關閉流
    outputStream.close();
}

讀取檔案內容

@Test
public void test5() throws Exception
{
    String path = "F:"+File.separator+"booway"+File.separator+"Java"+File.separator+"0711"+File.separator+"TestFile";
    File file = new File(path);

    FileInputStream inputStream = new FileInputStream(file);

    byte[] b = new byte[1024];

    int len = 0;
    int temp = 0;

    while ((temp = inputStream.read()) != -1)
    {
        b[len] = (byte) temp;
        len++;
    }
    inputStream.close();

    System.out.println(new String(b));

}

遍歷資料夾下第一級檔案或資料夾

@Test
public void test6()
{
    String path = "F:"+File.separator+"booway"+File.separator+"Java"+File.separator+"0711"+File.separator+"test";
    File file = new File(path);
    File[] files = file.listFiles();
    for (File file2 : files)
    {
        System.out.println(file2);
    }
}